Looked it up - - and it's really a cold food with seaweed and vinegar. It also uses cucumber. It's a Japanese food, so I can't translate it directly. It's just seaweed in sweet vinegar. I'll attach the recipe for you.

1 もずくが生もずくの场合はたっぷりの热汤に入れ、菜ばしでサッと混ぜてザルに上げ、流水で洗い、水気を切る。

2 キュウリは薄い轮切りにし、塩を振って軽くもむ。 Moisture ga outてきたら軽く绞る。

3 The vessel to be mokku, キュウリを入れ、＜合わせ酢＞を注ぐ.